Walking and primary prevention (2008)

Objective: To quantify the association between walking and the risk of cardiovascular disease (CVD) and all-cause mortality in healthy men and women.

Conclusions: The results suggest walking is inversely associated with clinical disease endpoints and largely support the current guidelines for physical activity. The mechanisms that mediate this relationship remain largely unknown and should be the focus of future research. The World Health Organization has stated that overall physical inactivity is estimated to cause 1.9 million deaths and 19 million disability adjusted life years globally. The current guidelines on cardiovascular prevention recommend at least 30 minutes of moderate intensity physical activity on five or more days of the week or 20 minutes of vigorous exercise on three days of the week. A substantial proportion of adults do not, however, achieve these guidelines, with an estimated 60% of the global population failing to meet minimum amounts of activity. Moderate intensity physical activities that can be incorporated into everyday life, such as walking, may be beneficial for improving adherence levels. Indeed, walking appears to be the preferred activity among sedentary individuals taking up physical activity. Much of the earlier epidemiological work has examined general leisure time physical activity or energy expenditure, but did not consider specific activities. A previous meta-analysis has shown beneficial effects of walking on blood pressure in controlled trials, although we are unaware of any work to date that has systematically reviewed walking as a specific activity in relation to chronic disease endpoints. The magnitude, dose-response relationship, and effectiveness of walking compared with more vigorous activities remain unclear. We therefore systematically reviewed evidence from prospective epidemiological studies of walking and cardiovascular disease (CVD) and all-cause mortality.

We primarily addressed four questions:

1. is walking associated with a risk of CVD and all-cause mortality?
2. are there any gender differences?
3. is walking volume or intensity more beneficial?
4. is there evidence of a dose-response relationship?